掺杂对γ－Fe_2O_3气敏元件灵敏度及其它特性的影响

本文着重研究了稀土氧化物及其它某些化合物对γ－Ｆｅ＿２Ｏ＿３气敏元件灵敏度、选择性、工作温度和使用寿命的影响，并对加粘土在γ－Ｆｅ＿２Ｏ＿３气敏元件中的作用做了详细研究，为制备优异的γ－Ｆｅ＿２Ｏ＿３气敏元件提供了实验依据。     

电弧等离子体法制备的纳米a—Fe2O3的气敏特性

用电弧等离子体法制备纳米ａ－Ｆｅ２Ｏ３并研究其气敏特性，结果表明，在没有掺杂的情况下，纳米ａ－Ｆｅ２Ｏ３就具有较好的气敏特性。其原因是纳米粒子具有较大的比表面积和较高的晶界比例，从而导致对气体的吸附能力的扩散能力增强。本文用原位ＸＲＤ方法研究了纳米ａ－Ｆｅ２Ｏ３的气敏机理，结果表明，在还原性气氛和加热条件下ａ－Ｆｅ２Ｏ３并没有被还原成Ｆｅ２Ｏ３其气敏机理主要是表面效应控制型。     

掺杂方式对α─Fe_2O_3气敏特性的影响

用化学沉淀法和升温水解法合成了纯α─Ｆｅ２Ｏ３和ＳｎＯ２掺杂的α─Ｆｅ２Ｏ３，用ＸＲＤ和ＴＥＭ研究了掺杂方式对α─Ｆｅ２Ｏ３微观结构的影响，用静态气敏测试方法研究了掺杂方式对α─Ｆｅ２Ｏ３气体灵敏度和电阻的影响结果表明：水解法α─Ｆｅ２Ｏ３颗粒微细（～４０ｎｍ），阻值适中（数百ｋΩ），而且气体灵敏度高     

电弧等离子体法制备的纳米α－Fe_2O_3的气敏特性

用电弧等离子体法制各纳米α－Ｆｅ＿２Ｏ＿３并研究其气敏特性，结果表明，在没有掺杂的情况下，纳米α－Ｆｅ＿２Ｏ＿３就具有较好的气敏特性。其原因是纳米粒子具有较大的比表面积和较高的晶界比例，从而导致对气体的吸附能力和扩散能力增强。本文用原位ＸＲＤ方法研究了纳米α－Ｆｅ＿２Ｏ＿３的气敏机理，结果表明，在还原性气氛和加热条件下，α－Ｆｅ＿２Ｏ＿３并没有被还原成Ｆｅ＿３Ｏ＿４，其气敏机理主要是表面效应控制型。     

掺锡对α—Fe2O3薄膜微结构和气敏特性的影响研究

本文用常压化学气相淀积法（ＡＰＣＶＤ）制备了α－Ｆｅ２Ｏ３薄膜，对所制备的薄膜进行了Ｘ射线衍射分析和表面形貌（ＳＥＭ）分析。对薄膜的气敏特性进行了测量。结果表明，用ＡＰＣＶＤ工艺制备的α－Ｆｅ２Ｏ３薄膜对烟者极为敏感并且具有良好的选择性；本研究还对所制备的α－Ｆｅ２Ｏ３薄膜进行了有效的掺杂，对掺杂样品的气敏特性测试表明四价金属元素Ｓｎ的掺入对α－Ｆｅ２Ｏ３薄膜的气敏特性有显著的影响。实验表明用ＡＰ     

EFFECT OF DOPING METHODS ON THE GAS-SENSING PROPERTIES OF α-Fe_2O_3

用化学沉淀法和升温水解法合成了纯α－Ｆｅ２Ｏ３和ＳｎＯ２掺杂的α－Ｆｅ２Ｏ３。用ＸＲＤ和ＴＥＭ研究了参杂方式对α－Ｆｅ２Ｏ３微观结构的影响。用静态气敏测试方法研究了掺杂方式对α－Ｆｅ２Ｏ３气体灵敏度和电阻的影响。结果表明：水解法α－Ｆｅ２Ｏ３颗粒微细（～４０ｎｍ），阻值适中（数百ｋΩ），而且气体灵敏度高。     

纳米ZnFe2O4气敏材料的结构和敏感特性研究

ＺｎＦｅ_２Ｏ_４是传统的铁氧体材料,近年来又发现具有良好的气敏性能．本文采用化学共沉淀法制备了纳米尺寸的ＺｎＦｅ_２Ｏ_４粉末,利用ＸＲＤ、ＸＰＳ、ＳＥＭ等手段研究了结构特性．以ＺｎＦｅ２Ｏ４纳米粉末为原料制备了厚膜气敏元件,测试了元件的气敏性能,并对气敏机理给予了解释．     

掺锑α－Fe_2O_3的结构和性能

用化学共沉淀与固相反应相结合的方法，在α－Ｆｅ＿２Ｏ＿３中掺入一定量的锑离子。Ｘ射线衍射（ＸＲＤ）分析表明，掺锑量（Ｓｂ／Ｆｅ原子比）小于０．２．材料仍保持小Ｆｅ＿２Ｏ＿３的晶体结构，但是加入量＞０．２时，有铁、锑复合氧化物生成。通过分析Ｓｂ的掺入对α－Ｆｅ＿２Ｏ＿３的晶粒生长及电学性质的影响，认为该系列材料的气敏性能有大幅度的提高，是锑的掺入改变了α－Ｆｅ＿２Ｏ＿３的气敏机理。     

掺锑a—Fe2O3的结构和性能

用化学共沉淀与固相反应相结合的方法，在ａ－Ｆｅ２Ｏ３中掺入一定量的锑离子。Ｘ射线衍射（ＸＲＤ）分析表明，掺锑量（Ｓｂ／Ｆｅ原子比）小于０．２，材料仍保持ａ－Ｆｅ２Ｏ３的晶体结构，但是加入量〉０．２时，有铁、锑复合氧化物生成。通过分析Ｓｂ的掺入对ａ－Ｆｅ２Ｏ３的晶粒生长及电学性质的影响，认为该系列材料的气敏性能有大幅度的提高，是锑的掺入改变了ａ－Ｆｅ２Ｏ３的气敏机理。     

电弧等离子体制备纳米ZnO的气敏特性

用Ｈ２＋Ａｒ电弧等离子体法制成纳米ＺｎＯ，ＺｎＯ－Ｆｅ，研究了其气敏特征及机理，结果表明：与其它制备方法相比，该方法制成的纳米ＺｎＯ气敏元件在没有贵金属掺杂的情况具有较高的灵敏度，工作温度为２００℃￣２５０℃，为常规元件的一半，纳米ＺｎＯ－Ｆｅ－Ｐｄ对液化石油气（ＬＰＧ）的选择性比纳米ＺｎＯ好，具有快速响应（〈１５ｓ）的恢复特性，能稳定地连续工作７０ｈ以上，可制作低功耗ＬＰＧ气敏元件。     

Degradation of C.I. Reactive Red 2 (RR2) using ozone-based systems: comparisons of decolorization efficiency and power consumption

This study investigated the decolorization efficiency of C.I. Reactive Red 2 (RR2) in O3, O3/H2O2, O3/Fe3+, O3/H2O2/Fe3+, UV/O3, UV/O3/Fe3+, UV/O3/H2O2 and UV/O3/H2O2/Fe3+ systems at various pHs. The effective energy consumption constants and the electrical energy per order of pollutant removal (EE/O) were also determined. The experimental results indicated that the energy efficiency was highest at [H2O2]0=1000mg/l and [Fe3+]0=25mg/l. Accordingly, the H2O2 and Fe3+ doses in the hybrid ozone- and UV/ozone-based systems were controlled at these values. This work suggests that the dominant reactant in O3, O3/Fe3+ and O3/H2O2 systems was O3 and that in the O3/H2O2/Fe3+ system was H2O2/Fe3+. The experimental results revealed that the combinations of Fe3+ or H2O2/Fe3+ with O3 at pH 4 and of H2O2 or H2O2/Fe3+ with UV/O3 at pH 4 or 7 yielded a higher decolorization rate than O3 and UV/O3, respectively. At pH 4, the EE/O results demonstrated that the UV/O3/H2O2/Fe3+ system reduced 85% of the energy consumption compared with the UV/O3 system. Moreover, the O3/H2O2/Fe3+ system reduced 62% of the energy consumption compared with the O3 system. At pH 7, the EE/O results revealed that the UV/O3/H2O2/Fe3+ system consumed half the energy of the UV/O3 system.     

Ni_(0.5)Zn_(0.5)Fe_2O_4铁氧体的制备及其电磁损耗性能

以Zn(NO3)2.6H2O、Ni(NO3)2.6H2O和Fe(NO3)3.9H2O及柠檬酸为原料,采用溶胶-凝胶法制备前驱体,在1 200℃下煅烧3 h合成ZnFe2O4和Ni0.5Zn0.5Fe2O4铁氧体粉体。利用差热分析、X射线衍射、扫描电镜、透射电镜和红外光谱等测试手段对产物进行分析和表征。结果表明:ZnFe2O4和Ni0.5Zn0.5Fe2O4属于立方晶系尖晶石结构,结晶完整,晶粒大小在100 nm左右。在0.2~1.8 GHz的频率下对产品进行了电磁损耗性能测试,发现Ni0.5Zn0.5Fe2O4具有较好的电磁损耗特性。     

Green synthesis of uniform magnetite (Fe3O4) nanoparticles and micron cubes

Single-crystalline Fe3O4 microcubes were obtained through a green hydrothermal procedure using Fe3+, Fe2+ and H2O2 as starting materials. The structures and morphologies of the as-prepared samples were characterized in detail by X-ray diffraction (XRD), Transmission electron microscopy (TEM) and scanning electron microscopy (SEM) respectively. Magnetite (Fe3O4) cubes averaging 3 microm in diameter were synthesized by H2O2 oxidation of Fe3+ and Fe2+ under neutral conditions. The contrastive experiments were designed to elucidate the effects of Fe3+, Fe2+ and H2O2 on the morphology of the final products. Irregular and ellipsoidal Fe2O3 structures were obtained by H2O2 oxidation of Fe3+ and Fe2+ respectively. Meanwhile, Fe3O4 nanotubes and nanoparticles were obtained when H2O2 was replaced by NH4HCO3 and urea respectively. The results show that H2O2, Fe3+ and Fe2+ in the reactive system play critical roles in obtaining micrometric cube-like Fe3O4. While, other nanometric Fe2O3 and Fe3O4 particles with tube-like and other morphologies could also be developed by controlling the reaction parameters.     

Synthesis of size-controlled Fe3O4@SiO2 magnetic nanoparticles for nucleic acid analysis

We present a systematic study on the preparation, characteration and potential application of Fe3O4 and Fe3O4@SiO2 nanoparticles. Fe3O4 nanoparticles of controllable diameters were successfully synthesized by solvothermal system with tuning pH. The magnetic properties of nanoparticles were measured by vibration sample magnetometer. Fe3O4@ SiO2 nanoparticles were obtained via classic St?ber process. Streptavidin coated Fe3O4@SiO2 nanoparticles were prepared by covalent interaction. The quantity of streptavidin bound to nanoparticles was determined by UV-Vis spectrometer. To evaluate the binding efficiency and capacity of nucleic acid on nanoparticles, the capture of biotinylated oligonucleotide on streptavidin coated Fe3O4@SiO2 nanoparticles at different concentration was estimated by fluorescence detection. Both Fe3O4 and Fe3O4@SiO2 nanoparticles exhibited well crystallization and magnetic properties. The maximal amount of streptavidin immobilized onto the Fe3O4@SiO2 nanoparticles was 29.3 microg/mg. The saturation ratio of biotinylated oligonucleotides captured on streptavidin coated Fe3O4@SiO2 nanoparticles was 5 microM/mg within 20 minutes, indicating that FeO4@SiO2 nanoparticles immobilized by streptavidin were excellent carriers in nucleic acid analysis due to their convenient magnetic-separation property. Therefore, the synthesized Fe3O4 and Fe3O4@SiO2 nanoparticles with controllable size and high magnetic saturation have shown great application potentials in nucleic acid research.     

氧化铁粉末化学组成对合成SHS复合弯管内衬陶瓷的影响

基于重力分离SHS法制备陶瓷内衬复合弯管 ,研究了氧化铁粉末化学组成对SHS复合弯管内衬陶瓷的影响 .研究发现在铝热剂相同质量分数条件下 ,存在于工业原料Fe2 O3 粉末的杂质比SiO2 添加剂对燃烧过程的稀释效应更为强烈 .在工业原料Fe2 O3 +Al体系中加入适量的Fe3 O4+Al体系 ,使燃烧温度、蔓延速率及SHS反应转化率均有所升高 ;但加入过量的Fe3 O4+Al体系 ,虽然使蔓延速率进一步增大 ,但却引起燃烧温度和SHS反应转化率有所下降 .实验表明 ,在工业原料Fe2 O3 +Al体系中加入 1 5 %的Fe3 O4+Al体系 ,使复合弯管内衬陶瓷性能达到并超过用分析纯Fe2 O3+Al体系所制备的复合弯管内衬陶瓷性能 .     

Fe3O4磁性纳米颗粒的合成与接枝聚合修饰（英文）

以氨水作为沉淀剂并控制溶液的pH值,采用Fe3+和Fe2+共沉淀法制得了磁性四氧化三铁纳米颗粒。合成的磁性纳米颗粒通过高分辨透射电镜、X射线衍射仪、傅里叶变换红外光谱仪进行了表征。四氧化三铁纳米颗粒的粒径约为10nm,其表面含有丰富的羟基。为了增强磁性四氧化三铁纳米颗粒和聚合物基质之间的相互作用,在纳米颗粒的表面接枝上乙烯基单体。傅里叶变换红外光谱仪和热重分析仪的测试结果显示,聚合物链共价结合在纳米颗粒表面。表面接枝聚合后,四氧化三铁纳米颗粒由极性转变为非极性。     

Effect of sintering temperature on the chemical bonding,electronic structure and electrical transport properties of β-Ga1.9Fe0.1O3 compounds

A model system,which is based on iron(Fe)doped gallium oxide(Ga₂O₃)(Ga_1.9Fe_0.1O₃),has been considered to elucidate the combined effect of transition-metal ion doping and processing temperature on the chemistry,local structure and chemical bonding,and electrical transport properties of a wide band gap oxide(Ga₂O₃).The Ga_1.9Fe_0.1O₃ compounds were synthesized using standard high-temperature solid state reaction method.The effect of processing conditions in terms of different calcination and sintering environments on the structural and electrical properties of Ga_1.9Fe_0.1O₃ compounds is studied in detail.Structural characterization by Raman spectroscopy revealed that Ga_1.9Fe_0.1O₃ compounds exhibit monoclinic crystal symmetry,which is quite similar to the intrinsic parental crystal structure,though Fedoping induces lattice strain.Sintering temperature(T_sint)which was varied in the range of 900-1200℃,has significant impact on the structure,chemical bonding,and electrical properties of Ga_1.9Fe_0.1O₃ compounds.Raman spectroscopic measurements indicate the proper densification of the Ga_1.9Fe_0.1O₃ compounds achieved through complete Fe diffusion into the parent Ga₂O₃ lattice which is evident at the highest sintering temperature.The X-ray photoelectron spectroscopy validates the chemical states of the constituent elements in Ga_1.9Fe_0.1O₃ compounds.The electrical properties of Ga_1.9Fe_0.1O₃ fully controlled by T_sint,which governed the grain size and microstructural evolution.The temperature and frequency dependent electrical measurements demonstrated the salient features of the Fe doped Ga₂O₃ compounds.The activation energy determined from Arrhenius equation is 0.5 e V.The results demonstrate that control over structure,morphology,chemistry and electrical properties of the Ga_1.9Fe_0.1O₃ compounds can be achieved by optimizing T_sint.     

CrO3对Fe2O3+Al铝热反应系统反应过程的影响

用铝热-重力分离法制备了不含铁铝尖晶石（FeAl2O4）的陶瓷内衬复合钢管，并通过热力学计算分析了有关反应的优先顺序，结果表明，在Fe2O3-Al系统中强氧化剂CrO3与Al的反应并不是一步完成而是分步反应，FeAl2O4优先于Cr2O3与Al反应，因而加入CrO3添加剂可有效地去除陶瓷层中的尖晶石相，从而提高复合钢管的耐蚀性能。     

纳米ZnFe_2O_4的制备及其光催化降解苯酚的协同效应

在干法室温条件下,利用滚压振动磨将金属锌制备成粒度大约40nm的锌粉,用化学共沉淀法制备粒度为10nm左右的Fe3O4。利用Zn-Fe3O4水解系统制备纳米ZnFe2O4,当温度达到300℃后,XRD图上明显出现ZnFe2O4的各个衍射峰,由透射电子显微镜可知,300℃和320℃时得到的纳米粒子都在20nm左右。分别用电子衍射、高分辨电镜对两个样品进行了表征。在距离6cm的30W紫外灯照射下,光催化降解苯酚的实验表明光催化降解的效率顺序为:ZnFe2O4-ZnO-Fe2O3>ZnO-Fe2O3>ZnFe2O4>ZnO>Fe2O3。     

Degradation of cyanobacteria toxin by advanced oxidation processes

Advanced oxidation processes (AOPs) using O(3), H(2)O(2), O(3)/H(2)O(2), O(3)/Fe(II), and Fenton treatment were investigated for the degradation of aqueous solutions of cyanobacteria. The effects of concentration of reactants, temperature, and pH on toxins degradation were monitored and the reaction kinetics was assessed. O(3) alone or combined with either H(2)O(2) or Fe(II) were efficient treatment for toxins elimination. A higher toxin oxidation tendency was observed with Fenton reaction; total toxins degradation (MC-LR and MC-RR) was achieved in only 60s. The ozonation treatment was successfully described by second-order kinetics model, with a first-order with respect to the concentration of either ozone or toxin. At 20 degrees C, with initial concentration of MC-LR of 1mg/L, the overall second-order reaction rate constant ranged from 6.79 x 10(4) to 3.49 x 10(3)M(-1)s(-1) as the solution pH increased from 2 to 11. The reaction kinetics of the other AOPs (O(3)/H(2)O(2), O(3)/Fe(II), and Fenton), were fitted to pseudo first-order kinetics. A rapid reaction was observed to took place at higher initial concentrations of O(3), H(2)O(2) and Fe(II), and higher temperatures. At pH 3, initial concentration of toxin of 1mg/L, the pseudo first-order rate constant, achieved by Fenton process, was in order of 8.76+/-0.7s(-1).